In Java, assertions are enabled by default in development and testing environments, but they can be disabled for production environments.

To disable assertions, you can use the -da (or -disableassertions) option when running the JVM.

Here is an example of how to disable assertions when running a Java program:

java -da MyApp

In this example, we disable assertions when running the MyApp class.

You can also disable assertions for a specific package or class by using the -da:<package> or -da:<package>.<class> options. For example:

java -da:com.mycompany.mypackage MyApp

In this example, we disable assertions for all classes in the com.mycompany.mypackage package.

It's important to note that assertions should not be used for normal error handling or input validation. Instead, they should be used to catch programming errors that should never occur during normal program execution. Assertions are typically used during development and testing to catch these errors early in the development process, but they should be disabled in production to avoid the performance overhead of checking assertions at runtime.